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资源说明：Scala library for talking to Riak
Riakka
======
Scala library for talking to Riak.
Getting started
---------------
You need to have SBT installed. Please follow [setup instructions](http://code.google.com/p/simple-build-tool/wiki/Setup).
git clone git://github.com/frank06/riakka.git
cd riakka
sbt
> update
> test
It assumes you're running Riak in `localhost` at port `8098`, and will use a random bucket starting with `riakka` to run the suite.
Riak
----
First off, you should be familiar with Riak. There is information available [here](http://riak.basho.com).
Some other resources of interest:
- [Riak Presentation at NYC NoSQL](http://riak.basho.com/nyc-nosql/)
- [Intro to Riak screencast](http://videocodechat.com/post/219711761/intro-to-riak-with-bryan-fink)
- [Riak Demo: Stickynotes](http://blog.beerriot.com/2009/08/17/riak-demo-stickynotes/)
- [Module jiak_resource Edoc](http://riak.basho.com/edoc/jiak_resource.html)
- ...and we're all looking forward to a wiki :)
Quick overview
--------------
Riak (through its HTTP interface, Jiak) exposes documents with some associated metadata (all in JSON format). For example:
{"bucket":"bucket", "key":"foo", "object":{"bar":"baz"}, "links":[["bucket","key","tag"], ["b2","key2","tag2"]]}"
Riakka will consistently return this structure splitted up in two: A tuple consisting of
- a metadata object (of type `%`) that holds important data such as `bucket`, `key`, `vclock`, `links`.
- the actual object (of type `JObject`) => see [lift-json](http://github.com/dpp/liftweb/blob/master/lift-base/lift-json)
Most query methods will also require a `%` object. There is a convenience method for creating those, as you will see in the following examples.
Features by example
-------------------
Fire a Scala console (within `sbt`):
> console
- first off, all the ceremony (wish it was more succint)
scala> import riakka._
scala> import Jiak._
scala> import net.liftweb.json._
scala> import JsonParser._
scala> import JsonAST._
scala> import JsonDSL._
- let's initialize the client and save an object
scala> val db = Jiak.init
scala> val json = parse(""" {"my":"json", "list": [1, 2, 3]} """)
scala> val metadata = %('test -> "mykey") // here we prepare a metadata object, with bucket test and key mykey
scala> db save (metadata, json)
- create a link (note the `save_with_response` method, that returns updated metadata!)
scala> val linked_json = ("am_i_being_linked?" -> true) ~ ("a", "b") // a neat DSL to create JSON
scala> val (linked_json_metadata, _) = db save_with_response (%('test -> "linked"), linked_json) // we persist that one
scala> val link = Link(linked_json_metadata) // we create the link _from_ a metadata object
scala> db save (metadata.link_+(link), json) // we pass-in a new metadata object, which contains the link
- walk the original object and retrieve the linked one
scala> val linked_objects = db walk (metadata, ^^('test)) // check the docs for ^^ / link-walking spec
scala> val (_, first_linked_object) = linked_objects first
scala> first_linked_object.to_json // right?
- now clean up
scala> db delete metadata // will use the metadata to locate the document and delete it
scala> db delete linked_json_metadata
scala> db get metadata // does the result make sense?
There is also support for `If-None-Match`, attachments and more. Have a look at `RiakkaSpec.scala`.
To be done
----------
- Much better support of the (known) HTTP API, including schemas (read/write masks), allow_mult, specifying R/W values and datastore info.
- Support for entities (as well as plain structs made up of Lists, Tuples, etc => all things convertable to JObject), transparent serialization/deserialization to/from JSON. Should be not a big deal, as lift-json supports it wonderfully.
- Make concepts more straightforward, improve documentation and test coverage, as usual.
Needless to say, fork and send pull requests. And make use of Github's issue tracker, too.
Citing [Paul from Ruby's RiakRest](http://github.com/wcpr/riakrest): "Go forth and Riak!"
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